dhl: Start with some empty stuff for a DHL tab

This tab will allow you to to manage coupon codes of DHL.

app/controllers/admin/dhls_controller.rb

@@ -0,0 +1,3 @@
+class Admin::DhlsController < Admin::BaseController
+  respond_to :html
+end

config/locales/en.yml

@@ -0,0 +1,4 @@
+---
+en:
+  dhl: DHL
+  dhls: DHL

config/routes.rb

@@ -1,3 +1,10 @@
 Rails.application.routes.draw do
   # Add your extension routes here
+  namespace :admin do
+    resources :dhls do
+      resources :coupons
+    end
+  end
+
+  match "/admin/dhl" => 'admin/dhls#index', :as => :admin
 end

lib/sysmocom_dhl_hooks.rb

@@ -1,3 +1,6 @@
 class SysmocomDhlHooks < Spree::ThemeSupport::HookListener
   # custom hooks go here
-end
+  insert_after :admin_tabs do
+      "<%= tab(:dhls) %>"
+  end
+end